Mordent with accidental shortcut

[Hans Aberg]

I want to make a shortcut for mordents with accidental below. One can  
use
  low = \once \override TextScript #'script-priority = #-100
  mordentsharp = \mordent^\markup{\sharp}
  ...
  \low f8\mordentsharp

But I would like to be able to skip the \low, here. So I thought of  
building it as a symbol, like in
the code below. But then the mordent and the sharp ends up side-by- 
side (see image below).

So how can this problem be fixed?

  Hans


----
\version "2.13.1"

mordentsharp=^\markup{\center-column
  {\line{\musicglyph #"scripts.mordent"}}
  \sharp
}

\score {
\new Staff <<
  \relative {
    f8\mordentsharp
  }
>>
  \layout { ragged-right = ##t }
}
----